An ultra thin flat panel display device has a display screen with a thickness of several centimeters. Especially, an LCD device among the flat panel display device is widely used for monitors of notebook computers, spacecrafts, and aircrafts, owing to features and advantages of low driving voltage, low power consumption, and portable size.
The LCD device includes a lower substrate, an upper substrate, and a liquid crystal layer formed between the substrates. Alignment of the liquid crystal layer is controlled depending on the presence of electric field and light transmittance is correspondingly controlled to display a picture.
However, the LCD device has a drawback of a narrow viewing angle range. To solve such a drawback, there were suggested a multi-domain LCD device, a vertically aligned (VA) mode LCD device, an in-plane switching (IPS) mode LCD device, and so on.
Of them, the IPS mode LCD device is designed to drive a liquid crystal through IPS generated between two electrodes formed in parallel. Hereinafter, a related art IPS mode LCD device will be described with reference to the accompanying drawings.
FIG. 1 is a sectional view illustrating a related art IPS mode LCD device, and FIG. 2A to FIG. 2D are sectional views illustrating a process of manufacturing a column space in a process of manufacturing an upper substrate of the related art IPS mode LCD device.
As shown in FIG. 1, a common electrode 12 and a pixel electrode 16 are formed in parallel on a lower substrate 10 by interposing an insulating film 14 therebetween.
A light-shielding layer 22 and a color filter layer 24 are formed on an upper substrate 20, and an overcoat layer 26 is formed on the light-shielding layer 22 and the color filter layer 24 to planarize the substrate 20.
A column spacer 30 is formed between the substrates 10 and 20 to maintain a cell gap. A sealant 40 is formed on outer regions of the substrates to bond the substrates 10 and 20 together. Also, although not shown, a liquid crystal layer is formed between the substrates 10 and 20.
At this time, the column spacer 30 is in contact with the lower substrate 10 by the bonding process between the substrates 10 and 20 after it is formed on the overcoat layer 26 of the upper substrate 20. A method of forming the column spacer 30 will now be described.
First, as shown in FIG. 2A, the overcoat layer 26 is formed on the upper substrate 20 where the light-shielding layer 22 and the color filter layer 24 are formed.
Then, as shown in FIG. 2B, a material 30a for the column spacer is formed on the overcoat layer 26.
Subsequently, as shown in FIG. 2C, a mask 38 having a predetermined pattern is disposed on the material 30a for the column spacer and light is irradiated thereon using a light irradiator (not shown).
Afterwards, as shown in FIG. 2D, the column spacer pattern 30 is completed by a developing process.
As described above, the column spacer pattern 30 is formed by the photolithographic process including the light irradiation and the developing process.
The photolithographic process has several drawbacks. First, the manufacturing cost increases because the photolithographic process requires the mask 38 and the light irradiator of high cost. Also, the process steps are complicated and the process time is long because exposing and developing processes are required.